Toothed plate-link chain

ABSTRACT

A toothed plate-link chain having a plurality of link plates that form chain links in the transverse direction of the chain. The link plates of laterally adjacent chain links partially overlap, and the chain links are hingedly connected to each other by hinge pins that extend through receiving openings in overlap regions of the link plates. At least some of the link plates have plate teeth, and some of the link plates have a modified form to reduce the effect of impact impulses of the link plates on the tooth flanks of a toothed wheel about which the chain passes. As a result, the magnitude of the meshing impulses and the times during which they act on the toothed wheel are modified to thereby reduce structure-borne noise.

The present invention relates to a toothed plate-link chain according to the preamble of Claim 1.

Toothed plate-link chains are known in many variants from the existing art. With a toothed plate-link chain that runs between two sprockets with a fixed transmission ratio, the impact impulse of the link plates on the tooth flanks of the sprockets causes a structure-borne noise to be introduced into the system, which results in a sound emission. The tooth meshing frequencies that arise due to this impact impulse are present at all rotational speeds. The rotational speed of the chain drive determines the frequency, which becomes higher the faster the chain drive rotates.

It is known to improve the acoustic properties of a toothed plate-link chain by randomizing the link plate lengths or randomizing the tooth flank contour. It is also known to effect an optimization of the sound emissions through parallel positioning of two toothed chains which run at an offset of half a link plate length to each other.

The present invention is based on the object of reducing the impact impulse of the link plates on the tooth flanks, and thus optimizing the strength of the meshing impulse and the time in which it acts on the sprocket.

This is achieved according to the present invention by a toothed plate-link chain having a plurality of link plates that form chain links in the transverse direction, where the link plates of adjacent chain links partially overlap and the chain links are connected to each other flexibly by joint pins that protrude through receiving apertures in an overlap zone of the link plates, and where at least part of the link plates have plate teeth, with part of the link plates having a profile modification of the plate teeth. In some chain links, the profile modification effects a change in the geometry of the tooth meshing between the toothed plate-link chain and an encircled sprocket as the chain meshes with the sprocket, compared to the other chain links. The link plates with profile modification thus mesh with the sprocket at a different interval and at a relatively deferred point in time compared to the link plates without profile modification. The meshing times are thereby situated unevenly around the circumference of the plate-link chain, so that for example when the toothed chain drive is rotating at a constant speed non-uniform meshing times of the respective chain links result. This prevents regular excitation of the plate-link chain to strand vibrations, which reduces the strand vibrations, in particular in resonances, due to the decreased excitation.

Preferably there is a provision that part of the chain links include a first link plate type, and a different part of the chain links contain the first link plate type as well as a second link plate type with a profile modification of the link plate teeth compared to the first link plate type. Thus the link plates with profile modification are situated irregularly in the plate-link chain. Thus there can be a provision that part of the chain links include only the first link plate type, and a different part of the chain links contain only the second link plate type, with a profile modification of the link plate teeth compared to the first link plate type. So in this case complete chain links are made either of the link plates without profile modification or of the link plates with profile modification.

The toothed plate-link chain can preferably include additional guide plates, which are either situated within the rows of link plates of the toothed plate-link chain or are situated at the lateral margins of the toothed plate-link chain as guide link plates.

Preferably there is a provision that the outer contour of all link plates is the same, and that the profile modification is effected by shifting the arrangement of receiving apertures for joint pins. Accordingly, the link plates with profile modification differ from the link plates without profile modification only in the position of the receiving apertures in the link plates. Preferably, it is also provided that the receiving apertures of the link plates with profile modification are moved to an upper side of the chain. As a result, the teeth of these link plates project further in the direction of the underside of the chain than is the case with the link plates without profile modification. As a result, the link plates with profile modification are more likely to come in contact with an encircled sprocket sooner as the link plate meshes with the sprocket than is the case with link plates without profile modification.

An alternative embodiment includes the provision that the outer contour of all link plates is the same, and that the profile modification is effected by an enlargement of the receiving apertures for the joint pins in the link plates, whereby the lash of the joint pins in the receiving apertures is increased. In addition or alternatively to the previously named shifting of the position of the receiving apertures, these are also enlarged, so that additional lash of the link plates results compared to the joint pins or to the rocker members of which the link pins are made.

Exemplary embodiments of the invention will now be explained on the basis of the accompanying drawing. The figures show the following:

FIG. 1: a detail of a toothed plate-link chain according to the existing art;

FIG. 2: a detail of a first exemplary embodiment of a toothed plate-link chain according to the invention, with a first exemplary embodiment of a link plate according to the invention;

FIG. 3: a link plate with receiving apertures according to the existing art and according to the first exemplary embodiment of the invention;

FIG. 4: a detail of a second exemplary embodiment of a toothed plate-link chain according to the invention, with a second exemplary embodiment of a link plate according to the invention.

FIG. 1 shows a detail of a toothed plate-link chain 1 according to the existing art in a cross-sectional side view. The figure depicts three adjacent chain links I, II and III, etc. To differentiate indications of direction, the direction designated in FIG. 1 as X will be designated hereinafter as the longitudinal direction of the chain, Y as the height direction and Z as the transverse direction. The height direction Y will be designated in the direction of the arrow Y as the direction of the top side of the chain, and opposite the direction of the arrow as the direction of the bottom side of the chain. Chain links I, II and III of the plate-link chain 1 include a plurality of link plates 2 that are stacked at intervals from each other in the transverse direction Z of the plate-link chain, and thus form chain links. The link plates 2 of adjacent chain links overlap each other in overlap zones 3. Receiving apertures 4 through which joint pins 5 protrude are situated in the overlap zones 3 of the link plates 4. Adjacent chain links are flexibly connected with each other by means of the joint pins 5. The joint pins 5 consist of two rocker members 6, 7, with each of the rocker members 6, 7 being connected to the link plates 2 of one of the chain links and the rocker members 6, 7 rolling on each other on pitch surfaces 8, 9. In the depiction in FIG. 1, rocker member 7 is connected to the link plates of chain link I, and rocker member 6 is connected to the link plates of chain link II. If tension is exerted on the toothed plate-link chain in chain longitudinal direction X, then pitch surfaces 8, 9 are pressed against each other, so that they touch each other at rocker member contact points 10. The rocker member contact point 10 of the two-dimensional depiction in FIG. 1 is a point; it of course extends in the transverse direction Z along the rocker members 6, 7 and thus in the three-dimensional depiction forms a contact line. The chain links 2 each include two teeth 11, which each have tooth flanks 12. The tooth flanks are differentiated in an outer flank 12 a and an inner flank 12 b. Not depicted in FIG. 1 and the subsequent figures are guide plates, which may be situated within the plate stack and serve to guide the toothed plate-link chain on a sprocket provided with a circumferential groove, or guide link plates that are situated on the outer sides of the toothed plate-link chain 1 in the transverse direction Z, and effect a guiding in the axial direction of a sprocket by encompassing the teeth of the sprocket.

FIG. 1 depicts a measure known from the existing art for reducing the meshing impulse as the toothed plate-link chain 1 meshes with a sprocket encircled by it. Chain links I, II, III etc. are made here of tooth plates, whose teeth 11 have differing outer contours of the tooth flanks 12. Thus two different types of link plates are used in the toothed plate-link chain, namely a first link plate type B with an outer contour of the tooth flanks of type B, and a second link plate type S with an outer contour of the tooth flanks of type S. The two link plate types B, S thus have a different outer contour, with the differences in the outer contour existing only in the area of the tooth flanks. To distinguish the two link plate types, one of the link plate types for example has an indentation 13 as a distinguishing feature when assembling the plate-link chain 1.

FIG. 2 shows a plate-link chain according to the invention in a depiction corresponding to FIG. 1. Here too, two link plate types are used, namely a first link plate type B, which is identical to the first link plate type B according to the exemplary embodiment in FIG. 1, and a second link plate type A, which has a profile modification Δγ of the tooth flanks 12 or of the teeth 11. In this case a profile modification Δγ means a complete shifting of the profile, and thus of the outer contour of the teeth 11 in the height direction Y of the plate-link chain 1. The profile modification is accomplished by the fact that while the outer contour of all of the link plates 2 is the same, the receiving apertures 4 in the second link plate type A are shifted relative to the receiving apertures 4 in the first link plate type. The possibility exists here that the inner contour of the receiving aperture 4 is identical, so that the receiving aperture 4 of the two link plate types is only positioned differently within the link plate, or that the receiving apertures 4 themselves have different inner contours. These two variant embodiments will be described below on the basis of FIGS. 3 and 4.

FIG. 3 shows the outer contour K of an exemplary embodiment of a link plate, where the outer contour K is identical for both link plate types as depicted previously. The two link plate types differ in the position of the receiving apertures, depicted by a dashed line 4.1 for the first link plate type B and with a solid line 4.2 for the second link plate type A. The position of the receiving apertures 4.1 or 4.2 can be defined by the rocker member contact point 10 when plate-link chain 1 is extended.

In the exemplary embodiment in FIG. 3 it is assumed that the outer flank 12 a is essentially a straight line segment. The distance from the tooth flank 12 to the rocker member contact point 10 is defined here by the distance between a line perpendicular to the outer flank 12 a that passes through the rocker member contact point 10 and a straight line 15 parallel to the perpendicular line 14, which touches the tooth flank 12. First link plate type B has a distance b from the tooth flank to the rocker member contact point 10, which is smaller than the distance a from the tooth flank to the rocker member contact point 10 of second link plate type A. The two link plate types can therefore be produced from the same semi-finished stock, by placing a receiving aperture 4 at different locations. In addition, a distinguishing feature such as an indentation 13 or the like can be placed on one of the two link plate types, as is customary in the existing art.

FIG. 2 shows a second exemplary embodiment of a plate-link chain according to the invention. Here the profile modification is effected by differing inner contours of the receiving apertures 4. The receiving apertures 4.2 of the second link plate type A have an inner contour that allows the joint pins 5 greater lash. This can be accomplished for example by increasing the lash of the rocker members of the adjacent chain links. This is explained in FIG. 4 on the basis of three chain links I, II, III corresponding to the designation in FIG. 1. The link plates 2 of chain link II have receiving apertures 4.2 that are enlarged in the direction of the top side of the chain, and thus enable greater lash for the associated rocker member 7. That shifts the link plate 2 of chain link II toward the top side of the chain, as identified by an arrow 16. The tooth flanks 12 of the second link plate type A then do not engage an encircled sprocket as early as the tooth flanks of the link plates of the first link plate type B. A plate-link chain 1 can be made up of link plates that include only one type of link plate. Hence there are then chain links that include only the first type of link plate, as well as chain links that include only the second type of link plate. The order of the chain links is arbitrary in this case; they can be situated alternately, or for example every second or every third or every fourth etc. chain link can consist of the one type of link plate and the other chain links can consist of the other type of link plate. It is equally possible, however, to install the different link plate types in mixed order in the chain links. For example, it is possible to use one link plate of a chain link of the one link plate type and all other link plates of the other link plate type. At the same time it is possible for example to equip only a small part of the chain links with the second link plate type and otherwise to use only the first link plate type, so that here disturbances of the meshing impulse can be brought about selectively to prevent chain strand vibrations.

REFERENCE NUMERAL LIST

-   1 toothed plate-link chain -   2 link plate -   3 overlap zone -   4 receiving aperture -   5 joint pin -   6 rocker member -   7 rocker member -   8 pitch surface -   9 pitch surface -   10 rocker member contact point -   11 tooth -   12 tooth flank -   13 indentation -   14 perpendicular line -   15 straight line -   16 arrow

SUMMARY

Toothed plate-link chain having a plurality of link plates that form chain links in the transverse direction, where the link plates of adjacent chain links partially overlap and the chain links are connected to each other flexibly by joint pins that protrude through receiving apertures in an overlap zone of the link plates, and at least part of the link plates exhibit plate teeth, with part of the link plates having a profile modification of the plate teeth. 

1. Toothed plate-link chain (1) with a plurality of link plates (2) that form chain links (I, II, III) in the transverse direction (Z), wherein link plates (2) of adjacent chain links (I, II, III) partially overlap, and the chain links (I, II, III) are flexibly connected to each other by joint pins (5) that protrude through receiving apertures (4) in an overlap zone (3) of the link plates (2), and wherein at least part of the link plates (2) have link plate teeth (11), characterized in that part of the link plates (2) have a profile modification (Δγ) of the link plate teeth (11).
 2. Toothed plate-link chain (1) according to claim 1, characterized in that part of the chain links include a first link plate type (B), and a different part of the chain links contain the first link plate type (B), as well as a second link plate type (A) with a profile modification (Δγ) of the link plate teeth (11) compared to the first link plate type (B).
 3. Toothed plate-link chain (1) according to claim 1, characterized in that part of the chain links include only the first link plate type (B), and a different part of the chain links contain only the second link plate type (A) with a profile modification (Δγ) of the link plate teeth (11) compared to the first link plate type (B).
 4. Toothed plate-link chain (1) according to claim 2 or 3, characterized in that the toothed plate-link chain (1) includes guide plates in addition.
 5. Toothed plate-link chain (1) according to claim 4, characterized in that the guide plates are guide link plates.
 6. Toothed plate-link chain (1) according to one of the preceding claims, characterized in that the outside contour (K) of all link plates (1) is the same, and the profile modification (Δγ) is achieved by shifting the positioning of receiving apertures (4) for joint pins (5) in the link plates (2).
 7. Toothed plate-link chain according to claim 6, characterized in that the receiving apertures (4) in the link plates with profile modification (Δγ) are shifted toward an upper side of the chain.
 8. Toothed plate-link chain according to one of the preceding claims, characterized in that the outside contour (K) of all link plates (2) is the same, and the profile modification (Δγ) is effected by an enlargement of the receiving apertures (4) for the joint pins (5) in the link plates (2), whereby the lash of the joint pins (5) in the receiving apertures (4) is increased. 